CELLULAR ACTIONS OF THE CATECHOLAMINES

儿茶酚胺的细胞作用

• 批准号: 3336286
• 负责人: JOHN P BILEZIKIAN
• 金额: $ 28.6万
• 依托单位: COLUMBIA UNIV NEW YORK MORNINGSIDE
• 依托单位国家: 美国
• 财政年份: 1977
• 资助国家: 美国
• 起止时间: 1977-05-01 至 1991-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3336286
• 关键词: G protein; adenosinetriphosphatase; adenylate cyclase; beta adrenergic receptor; beta antiadrenergic agent; biological information processing; catecholamines; cations; cell differentiation; cell membrane; chemical structure function; cyclic AMP; diagnostic tests; drug metabolism; erythrocyte membrane; guanine nucleotides; guanosinetriphosphatases; hormone receptor; hormone regulation /control mechanism; human tissue; ion transport; isoproterenol; laboratory rat; lipids; liver pharmacology; membrane permeability; ouabain; pertussis toxin; phosphorylation; propranolol; radiotracer; reticulocytes; sodium potassium exchanging ATPase; stereoisomer; thermodynamics; thyroid hormones; turkeys

The investigation seeks to establish definitive evidence for the function of a guanine nucleotide regulatory protein in a pathway of cellular catecholamine action different from that associated with activation or inhibition of adenylate cyclase. The mechanisms of alpha1-adrenergic action will be studied in the cultured rat myocardial cell. This cell converts its response to alpha1 agonist stimulation from an increase to a decrease in rate of beating in association with the functional acquisition of a 41K ADP-ribosylatable substrate for pertussis toxin. The specific aims are to define the role of the pertussis toxin substrate in the chronotropic effects of the alpha1-adrenergic catecholamines in cultured cardiac cells; and to establish the role of the pertussis toxin substrate in the actions of the alpha1-adrenergic catecholamines to stimulate phosphatidylinositol turnover and to increase cytosolic calcium concentrations in myocytes. The effect of alpha1 agonist to stimulate phosphatidylinositol turnover and to activate the enzyme, phospholipase C, implicated as the site of alpha1 agonist action, will be determined. Cytosolic calcium will be measured by fluorescent probes in suspended cells and by fluorescence microscopy of isolated single myocytes. The second major objective is to purify a cytosol regulator of adenylate cyclase activity obtained from rat reticulocytes, and to determine its mechanism of action. Reticulocyte cytosol activator protein (RCAP) augments adenylate cyclase activity at the level of the guanine nucleotide regulatory proteins. RCAP will be purified to homogeneity. The site at which and mechanisms by which RCAP interacts with the guanine nucleotide proteins will be established. The major effect of RCAP upon the pertussis toxin substrate, Ni, observed in all tissues studied so far, suggests a potential role for RCAP in the regulation of the non-cyclic AMP associated pathway of alpha1-adrenergic action to be studied in the myocardial cell. Methods to be employed include new biochemical approaches to protein purification, isolation of the guanine nucleotide binding proteins, GTP binding and GTPase assays of the alpha subunits of N under the influence of RCAP. Further understanding of the cellular actions of the catecholamines resulting from these investigations is likely to provide a framework with which abnormalities of catecholamine function can be more completely appreciated.

调查旨在为该功能建立明确的证据 鸟嘌呤核苷酸调节蛋白在细胞通路中的作用 儿茶酚胺作用不同于与激活或相关的作用 抑制腺苷酸环化酶。 α1-肾上腺素能的作用机制 将在培养的大鼠心肌细胞中研究其作用。 这个细胞 将其对 alpha1 激动剂刺激的反应从增加转变为 与功能获得相关的搏动率降低 百日咳毒素的 41K ADP-核糖基化底物。 具体的 目的是确定百日咳毒素底物在 α1-肾上腺素儿茶酚胺在培养物中的变时作用 心肌细胞；并确定百日咳毒素底物的作用 α1-肾上腺素儿茶酚胺的作用，以刺激 磷脂酰肌醇周转并增加细胞质钙 肌细胞中的浓度。 α1激动剂的刺激作用 磷脂酰肌醇周转并激活磷脂酶 C， 所涉及的α1激动剂作用位点将被确定。 将通过悬浮细胞中的荧光探针测量胞质钙 并通过荧光显微镜观察分离的单个肌细胞。 第二个 主要目标是纯化腺苷酸环化酶的胞质调节剂 从大鼠网织红细胞中获得活性，并确定其机制 行动。 网织红细胞胞质激活蛋白 (RCAP) 增强腺苷酸 鸟嘌呤核苷酸调节水平的环化酶活性 蛋白质。 RCAP 将被纯化至同质。 的站点和 RCAP 与鸟嘌呤核苷酸蛋白相互作用的机制 将成立。 RCAP对百日咳毒素的主要作用 迄今为止在所有研究的组织中观察到的底物 Ni 表明潜在的 RCAP 在调节非环 AMP 相关途径中的作用 待研究心肌细胞中的α1-肾上腺素能作用。 方法 采用的包括新的生物化学方法来纯化蛋白质， 鸟嘌呤核苷酸结合蛋白、GTP结合和的分离 RCAP 影响下 N α 亚基的 GTP 酶测定。 进一步了解儿茶酚胺的细胞作用 这些调查的结果可能会提供一个框架 哪些儿茶酚胺功能异常可以更彻底 赞赏。